Markets: Small-to-Midsize Municipalities

Tata & Howard team members provided engineering services to The Dexter Utility District to evaluate their existing wastewater treatment facility and to provide wastewater treatment facility design. It was recommended that a phased approach to upgrade the facility be utilized in order to reduce the initial impact on the sewer user rates. The first phase of the improvements combined improvements which would improve the reliability and obtain energy savings with cleaning and disposing of sludge for the first time from their 25 year old facility. This approach allowed for a grant loan financing package to be utilized. The first phase facility upgrade included replacing a leaking single air header main with two individual air headers, replacing course bubble diffusers with fine bubble membrane diffusers, replacing three 25 year old blowers with new blowers with variable speed drives. The speed of the new blowers is controlled by a PID loop using dissolved oxygen analyzers, to maintain optimum treatment and minimize energy consumption. These improvements have reduced the energy consumption at the wastewater treatment facility by more than 50 percent.

Tata & Howard has been working with the Town of Hopedale, Massachusetts for a number of years on a variety of wastewater collection and treatment projects. When the Town received an administrative order to address copper and ammonia violations at the plant, they turned to Tata & Howard for assistance. We completed the design and construction of a Wastewater Treatment Facility Upgrade project which included the installation of an automated soda ash feed system and an integrated fixed film activated sludge system (IFAS). The IFAS system is an innovative biological treatment process using thousands of special carriers designed to increase total surface area for biofilm growth without expanding the plant’s footprint. The blowers were also modified to provide better control over the aeration process.

A pilot study was conducted to test the ability of various reagents to facilitate the removal of copper from the waste stream. An automated chemical addition system was designed to improve coagulation. Additionally, a dynamic tangential filter was incorporated into the upgrade project. These improvements have allowed the Town to now meet its discharge limits for ammonia and copper.

Tata & Howard provided water and wastewater engineering services associated with the update of existing water and sewer system models using InfoWater and InfoSewer computer programs; review of the impact of proposed developments and proposed extensions to the City’s systems; verification of the hydraulic models for the City of Goodyear’s water distribution and wastewater collection systems. The water model included fire flow testing, C-value tests and calibration of the InfoWater hydraulic model. The wastewater collection system model included installation of six flow monitoring stations in three sub-basins, calibration of the model, development of a cost allocation model, and preparation of a technical report.

Tata & Howard prepared a facilities plan for the Corgett Water Reclamation Facility. The plan addressed the need for process redundancy and recommended improvements for increased flows and Class A+ effluent. Provided ongoing support services to address operational needs and to assess the impact of new developments on the system. Provided design, bidding, construction administration, resident observation, and construction services associated with improvements to the Corgett WRF including: filter system, low lift pump station, modifications to the sand filter, and instrumentation upgrades.

Tata & Howard is currently providing construction administration services for a new 0.5 million gallon cast-in-place concrete water storage tank, booster pump station, approximately 12,600 linear feet of new 12-inch diameter water main, and miscellaneous distribution system upgrades. Construction of in-line isolation valves, removal of existing pressure-reducing valve (PRV) vaults, a new system wide SCADA system and new high lift pumps at the water treatment facility and well site were also included in Tata & Howard’s design. The purpose of this project is to separate the current single zone system into two pressure zones as required by an Administrative Consent Order from the MassDEP.

The creation of a two pressure zone system requires the replacement of the existing 200 horsepower (hp) pump at the Meadow Road Water Treatment Facility and 150 hp pump at the Cranberry Brook Well with lower head, high efficiency pumps and motors. The Meadow Road facility is the Town’s primary water supply source; therefore, changing of this pump requires coordination with the Department of Utilities and Facilities and the overall two pressure zone project construction sequencing to minimize the time this source is off-line.

Tata & Howard also verified the Town’s hydraulic model, which was used to select the best location for the new tank and select water main size for transmission and fire protection. The model was also used to determine the boundary line between the two pressure zones. A Capital Efficiency Plan™ is currently being prepared. Assistance will be provided, as needed, for public education of the project and during Town meetings. This project is being funded by the American Recovery and Reinvestment Act through the Massachusetts State Revolving Fund (SRF). Due to an aggressive schedule required under the funding requirements, all design; permitting associated with planning, zoning, and wetlands; and project bidding were completed and approved within a six-month period.

Tata & Howard first assisted the District with responses to the Water Supply Division Sanitary Survey and then developed alternatives for the long term plan that would address all of the deficiencies and meet compliance with the Federal and State drinking water rules. The issues were as follows:

Wooden roof over concrete storage tank

Inadequate disinfection system and metering of source

Inadequate system pressures at the highest points within the system

Water losses

Inadequate metering of sources of supply to the storage tank

Inadequate distribution piping for fire flows.

The solutions developed were as follows:

Design and installation of concrete precast cover on storage tank

Design of new building at storage tank with flow measurement and disinfection and better storage tank access for cleaning

Virtual abandonment of auxiliary springs and surface water emergency source

Design of water main replacement to meet required system pressures for compliance with the drinking water standards and rules

Locating, permitting and developing a new source of supply (well) to supplement the existing wells and virtually eliminate the old spring sources due to the potential for contamination that had occurred in the past.

Securing the maximum amount of grant funding available to the District at 45% with the remainder a low interest loan.

Tata & Howard has been working with the District assisting them to come into compliance with the deficiencies noted in their Sanitary Survey. This District was once a private water company with numerous water quality, pressure, and supply issues and it finally was turned into a Fire District. The system has 45 connections and is on a water connection ban from the State. Tata & Howard prepared a Water Supply Feasibility Study with regards to addressing all of the systems issues, which are noted below:

Issues with the spring source and its spring house structure

Issues with inadequate system pressure at a few connections

No disinfection system or stand by disinfection system

Lack of source metering

Lack of source overflow metering

Lack of auxiliary well approval

Lack of system flushing hydrants

Lack of good water system map

Inadequate supply during summer months due to reduction in spring source

Failed coliform tests requiring disinfection

The solutions developed included the following:

New spring house roof and structure for disinfecting

Computer modeling for alternatives to address inadequate flows and pressures

Tata & Howard provided engineering services associated with water supply upgrades for Canaan FD #1 & #2. These two districts are located about 1.5 miles apart, meet monthly, and have one operator. For FD#2, located in Beecher Falls, VT, Tata & Howard completed construction of a new concrete storage tank, well upgrades, and distribution system improvements including significant replacement of pipe. Tata & Howard was able to secure a 75% grant for the project which resulted in little impact to their water rates.

A new storage tank at an elevation that would eliminate all pressure issues

Distribution piping replacement and addition of hydrants of flushing and fire protection

Reduction in water losses allowing for reduced well pump size, resulting in lower annual power and chemical costs

Fire District #1

FD#1 has two sources of supply. One is a large spring system located in Canada which consists of ten springs connected together, all under the influence of surface water and the other is a high yielding well source in the town limits. The issues are inadequate spring source construction and ability to maintain, low system pressures across the State line (they provide water service to West Stewartstown, NH), inadequate flushing capabilities, inadequate distribution piping, high iron and manganese levels in well source, and inadequate storage tank.

The solutions include the following:

Elimination of the spring sources due to Canadian border issues and high cost for upgrading the springs and connection piping

Advanced condition assessment of cast iron water main samples and water infrastructure provides insight into the quality and reliability of a water distribution system. The goal is to be able to efficiently and effectively run the water distribution system by allocating capital to areas of the system that are in need of rehabilitation or replacement. Tata & Howard is a leader in condition assessment methods for water distribution system pipe assets.

In 2007, Tata & Howard began extracting one foot long cast iron water main samples ranging in diameter from 6 to 12 inches as part of a cleaning and cement lining water main rehabilitation project. Since then, we have evaluated a significant number of cast iron water main samples for several water distribution systems throughout Massachusetts and Connecticut, typically during a rehabilitation project, water main failure, or water main replacement project.

Sections are evaluated using several criteria:

Pipe Class Estimation Based on Remaining Wall Thickness

Visual Inspection

Pipe Crushing ANSI A21.6-13 Yields Break Load of SampleSamples are loaded, one at a time, onto a machine that monitors the application of load in pounds, and the load required to cause the main to break is then recorded. Additional visual inspections are also made and recorded.

Remaining Factor of Safety Estimation

In the past, cast iron pipe manufacturers incorporated a 2.5 minimum factor of safety (FOS) to the crushing load necessary to break a water main. The manufacturer’s FOS can be compared to the crushing load that was measured at the materials testing facility, which then yields the estimated remaining FOS of the water main sample.

Condition assessment is beneficial in assisting a utility in the decision to rehabilitate a water main or schedule it for replacement, and in identifying asset classes that are candidates for replacement. The visual inspection provides an assessment of the quality of the water main, which assists in properly allocating capital funds to mains that are on the verge of failure or in need of rehabilitation.

Whitepaper:

Pipe condition assessment combined with break data for New England communities allows for continued analysis of problem pipes in distribution systems. This whitepaper outlines the research completed and the data collected to help pinpoint the next problematic pipe cohort. Read the complete whitepaper by clicking below:

Tata & Howard provided evaluation, planning, funding assistance, design, and construction phase engineering services for an upgrade to the 30-year old 0.750 MGD Extended Aeration Activated Sludge Treatment facility including conversion to Anoxic/Oxic activated sludge process to allow more operations’ flexibility, reduce construction and annual O&M costs, and prepare for potential for nutrient removal. Improvements consisted of the construction of four anoxic basins and four oxic basins, replacement of clarifiers, addition of five blowers, new electrical and control building, new heating system, new influent pumps, headworks influent screen followed by grit removal, centrifuge for sludge dewatering and post sludge dry storage building for the Class A Sludge. The project was funded by a USDA Rural Development loan and grant.